In certain refrigeration systems, for example a split system air conditioning unit, a service valve assembly is used to provide access to various parts of the system during manufacture as well as after installation of the system. A split system air conditioning unit is a unit that has the condenser unit mounted in a different location than the evaporation unit. The central air conditioning system in most homes is an example of a split system, with the condenser unit located outside of the home, and the evaporation unit located in the furnace.
FIG. 1 illustrates a conventional service valve assembly 2 that has a housing 4, a condenser side port 6, and an evaporation side port 8. A piston 10 is disposed inside the housing and is used to isolate the condenser side of the refrigeration system or allow a flow path between the evaporation side and the condenser side. A removable cap 12 is secured to the housing 4 and is removed to provide access to the piston 10 so the piston can be rotated to change the position of the piston in the housing between the isolation position shown in FIG. 1 to a position permitting flow between the evaporation side and the condenser side. An access valve 14 provides access to the interior of the housing 4 for use in servicing the refrigeration system to which the assembly 2 is connected.
In typical use, the condenser side port 6 of the valve assembly 2 is connected to the condenser unit at the factory. The piston 10 is actuated outward to provide a flow path between the evaporation side and the condenser side. The manufacturer will attach to the evaporation side port 8 using suitable tooling and test for leaks, evacuate the system of air/contaminants, and charge with refrigerant. The piston 10 is then closed to isolate the condenser side and the tooling is removed. Processing can occur through the access valve 14, but it is more typical to process through the evaporation side port 8. Once the system is ready for installation, the evaporation side port 8 is connected to the evaporation coil. The installer and downstream service personnel can then attach servicing tools to the access valve 14 to evacuate the system or perform other servicing functions, and the piston 10 opened again to allow the flow of refrigerant between the condenser and evaporator side.